Ka-band dual circularly polarized transceiver antenna for medical applications

A Ka-band circularly polarized transceiver antenna for Blood flow velocity measurement is presented by the simulation method in this paper. To realize circular polarization and integrative transceiver, a quadrature hybrid with two ports is used to offer phase difference. According to the simulation result, the antenna has a high gain as well as great Front-to-Back ratio. Meanwhile, the input isolation is quite high in the operation frequency (29.8GHz). At that frequency, the maximum Doppler frequency shift can achieve hundreds of Herz which will greatly improve the measuring resolution. Moreover, the size of the antenna is very compact so that it can get higher accuracy when detecting arteries or venae about 3~5mm in diameter.